# ---
# title: 15. 3Sum
# id: problem15
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Array, Two Pointers
# link: <https://leetcode.com/problems/3sum/description/>
# hidden: true
# ---
# 
# Given an array `nums` of _n_ integers, are there elements _a_ , _b_ , _c_ in
# `nums` such that _a_ \+ _b_ \+ _c_ = 0? Find all unique triplets in the array
# which gives the sum of zero.
# 
# Notice that the solution set must not contain duplicate triplets.
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: nums = [-1,0,1,2,-1,-4]
#     Output: [[-1,-1,2],[-1,0,1]]
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: nums = []
#     Output: []
#     
# 
# **Example 3:**
# 
#     
#     
#     Input: nums = [0]
#     Output: []
#     
# 
# 
# 
# **Constraints:**
# 
#   * `0 <= nums.length <= 3000`
#   * `-105 <= nums[i] <= 105`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
